A subscriber identity module (SIM) is a telecommunication chip card that securely stores the service-subscriber key (IMSI) used to identify a subscriber on mobile telephony master devices, such as mobile phones and other electronic appliances that have an interface to a telecommunication network. The SIM card allows users to change phones by simply removing the SIM card from one mobile phone and inserting it into another mobile phone or other telephony device.
A SIM card contains a unique serial number, international unique number of the mobile user (IMSI), security authentication and ciphering information, and two passwords (a PIN for usual use and a PUK for unlocking).
The use of SIM cards is mandatory in GSM master devices. The equivalent of a SIM card in UMTS is called the universal integrated circuit card (UICC), which runs a USIM application. The UICC is also referred to as a USIM chip card in the prior art.
A USIM chip card implements the UMTS telecommunication standard while being downward-compatible to the GSM telecommunication standard. Hence, a USIM chip card can be inserted into the chip card reader of both UMTS and GSM master devices.
DE10 2005 045483 A1 discloses a mobile phone comprising a SIM card wherein a common blocking code may be used for blocking the mobile telephone and the SIM card.
WO 2005/096649 A relates to a telecommunications system for mobile radio telephone services with mobile terminals with subscriber cards which are located inside the mobile terminals or can be inserted therein. Said subscriber cards comprise a SIM application and a USIM application and switching means that enable a switching between a first and a second operating mode. The SIM application is active in the first operating mode and the USIM application is active in the second operating mode. Switching between the first and second operating mode is achieved by for example receiving a certain switching signal from a provider of a mobile telecommunications network.